JPS6130144B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates primarily to a secondary air introduction device for engines for automobiles and other vehicles.

Conventionally, in this type of device, a differential pressure responsive control valve having a chamber on one side of a diaphragm and a chamber on the other side of a diaphragm that communicate with each other via a throttle is installed in a secondary air introduction passage connected to an intake passage of an engine. When the engine is decelerating, the negative pressure generated on the downstream side of the throttle valve in the intake passage is guided from the negative pressure outlet into the chamber on one side via the negative pressure passage, causing the valve to open. There is a known system in which secondary air is introduced into the combustion chamber of the engine through this to prevent the afterburn phenomenon, but in this case, the chamber on the other side is connected to the atmosphere. This is a general expression that is blocked.
In such a valve, when the valve is opened, the negative pressure in the chamber on the one side is guided into the chamber on the other side through the throttle, and the differential pressure is eliminated relatively quickly. The valve closes relatively quickly, for example within a few seconds, and the amount of secondary air introduced is relatively small, which may be undesirable depending on the operating conditions of the engine. For example, when the engine is at a low temperature, the chioke valve is on the closed side, so if you decelerate in this state, the air-fuel ratio in the combustion chamber becomes extremely rich, and unburned components in the exhaust gas become
This increases the amount of HC and CO emissions, and is therefore unsuitable for small amounts of secondary air.

It is an object of the present invention to provide a device that eliminates such inconveniences, and the secondary air introduction passage connected to the intake passage of the engine is provided with a chamber on one side of a diaphragm and another chamber on one side of a diaphragm that communicates with each other via a throttle. When the engine is decelerating, the negative pressure on the downstream side of the throttle valve in the intake passage is supplied to the intake passage from the negative pressure outlet through the negative pressure passage. In a device in which the valve is guided into a chamber on the other side and given an opening side operation, negative pressure is supplied to the chamber on the other side to a negative pressure outlet slightly upstream of the closed position of the throttle valve in the intake passage. It is characterized in that it is communicated through a passage and that a valve that opens and closes depending on the operating state of the engine is interposed in the negative pressure passage.

Embodiments of the present invention will be described with reference to attached drawings.

In the drawings, 1 indicates the intake passage of the engine, 2 indicates the carburetor on the upstream side thereof, 3 indicates the throttle valve, 4 indicates the choke valve, and 5 indicates the air cleaner at the upstream end.
A secondary air introduction path 6 is provided which is branched from the downstream side thereof and communicated with the atmosphere via the air cleaner 5, and a secondary air control valve 7, that is, an anti-afterburn valve is intervened in this. The control valve 7 is configured as a differential pressure responsive type having a chamber 10 on one side and a chamber 11 on the other side that communicate with each other via a throttle 9 formed in a diaphragm 8. The chamber 10 is connected to a negative pressure outlet 13 on the downstream side of the throttle valve 3 in the intake passage 1 through a negative pressure passage 12 connected thereto, so that when the engine is decelerated, the negative pressure is generated on the downstream side. Negative pressure is introduced from the outlet 13 through the passage 12 into the chamber 10 on one side, and the valve 7 is opened;
Secondary air is guided through this, and then the chamber 10 on one side passes through the throttle 9 to the chamber 11 on the other side.
The differential pressure between the two is eliminated, the valve 7 is closed, and the introduction of secondary air is stopped. In the drawings, reference numeral 14 indicates an intermediate throttle of the secondary air introduction path 6.

Although the above is not particularly different from the conventional one, according to the present invention, the throttle valve 3 of the intake passage 1 is connected to the second negative pressure passage 15 in the chamber 11 on the other side. The chamber 11 is connected to the second negative pressure outlet 16 slightly upstream of the closed position, so that the inside of the chamber 11 is connected to the second negative pressure outlet 16 on the upstream side of the closed position.
The negative pressure inside was channeled away. A valve 17 for opening and closing the passage 15 is provided in the passage 15, and the valve 17 is of a type that opens at a low temperature of the engine, for example, a cooling water temperature of 75° C. or lower. That is, the valve 17 is actuated by the actuating solenoid 1.
The solenoid 17a is configured as a solenoid valve that opens when the solenoid 7a is energized, and the solenoid 17a is connected to the power source 19 via a water temperature sensor 18 consisting of a switch that detects low water temperature and closes.
The relay contact 20a is interposed between the water temperature sensor 18 and the solenoid 17a.
The relay coil 20 is connected to the power source 19 via a vehicle speed sensor 21 consisting of a switch that closes at high vehicle speeds, so that the valve 17 remains open even at high vehicle speeds.

Both chambers 10 and 1 are designed to quickly stop the introduction of secondary air when switching from deceleration to acceleration of the engine.
It is preferable to eliminate the differential pressure between the chambers 11 and 11 as quickly as possible, which is advantageous for improving drivability. is communicated with the negative pressure passage 12 leading to the chamber 10 on one side via a side passage 23 having a throttle 22, so that negative pressure can also be introduced into the passage 15 through this.

Further, when the vehicle speed is low, for example, 20 km/h or less, or when the vehicle is stopped, the introduction of secondary air is not necessarily necessary, and it is conceivable to stop the introduction of secondary air. The system shown in FIG. 2 satisfies such requirements, and includes a valve 24 in the negative pressure passage 12 that is closed at low vehicle speeds. The valve 24 is a solenoid valve that opens when the solenoid 24a is energized.
4a is connected to the power source 19 via the vehicle speed sensor 21 described above.
Accordingly, since the sensor 21 opens at low vehicle speeds, the valve 24 is de-energized and closed. With this closure, no negative pressure is introduced into the chamber 10 on one side, and thus the control valve 7 is kept inoperative, in other words, no secondary air is introduced at all. .

To explain its operation first with respect to the one shown in the first diagram, depending on the low temperature of the engine and the high speed of the vehicle, the valve 1
7 is opened and the inside of the chamber 11 on the other side communicates with the inside of the negative pressure outlet 16. Therefore, when the throttle valve 3 is set to the closed side in order to reduce the speed next time, the inside of the negative pressure outlet 16 becomes approximately atmospheric pressure. , a pressure difference is generated between the two chambers 10 and 11, and the control valve 7
is opened and secondary air is conducted through it. The valve 7
is then closed when the pressure difference between the two chambers 10 and 11 is eliminated, but since the inside of the chamber 11 on the other side exists at approximately atmospheric pressure, it takes some time to eliminate the pressure difference. The valve 7 is open for a relatively long time and admits a relatively large amount of secondary air, which meets the requirements mentioned above.
Next, when the engine becomes hot, the water temperature sensor 18 opens, the valve 17 closes, and the interior of the chamber 11 on the other side is substantially sealed, so that the control valve 7 operates in substantially the same manner as the conventional one. That is, when the engine is decelerated, a relatively small amount of secondary air is introduced. This also applies to low vehicle speeds. In addition, when operating with the valve 17 open as described above, considering the case where the engine switches from deceleration to acceleration, the inside of the negative pressure outlet 16 becomes a relatively large negative pressure, and the pressure between the two chambers 10 and 11 increases. The differential pressure is eliminated, and in this case, the above-mentioned side passage 23 acts to speed up the elimination of the differential pressure, thus improving drivability.

Furthermore, in the second diagram, the following operations are added. That is, the valve 24 is closed at low vehicle speeds,
Thus, even when the engine is decelerated, no negative pressure is introduced into the chamber 10 on one side, and the control valve 7 is kept inoperative. In other words, the valve 7 remains completely inactive.

As described above, the present invention allows a relatively large amount of secondary air to be introduced during deceleration when the engine is at a low temperature, and has the effect of eliminating the above-mentioned disadvantages of the conventional engine.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of one example of the apparatus of the present invention, and FIG. 2 is an explanatory diagram of a modification thereof. 1... Intake passage, 3... Throttle valve, 6... Secondary air introduction path, 7... Control valve, 8... Diaphragm,
9... Throttle, 10... Chamber on one side, 11... Chamber on other side, 12... Negative pressure passage, 13... Negative pressure outlet, 1
5... Negative pressure passage, 16... Negative pressure outlet, 17...
Valve, 18...Water temperature sensor.

Claims (1)

[Scope of Claims] 1. A differential pressure-responsive control valve having a chamber on one side of a diaphragm and a chamber on the other side of a diaphragm that communicate with each other via a throttle is provided in a secondary air introduction passage connected to an intake passage of an engine. When the engine is decelerating, the negative pressure on the downstream side of the throttle valve in the intake passage is guided from the negative pressure outlet into the chamber on one side through the negative pressure passage, causing the valve to operate on the opening side. The chamber on the other side is communicated with a negative pressure outlet slightly upstream of the throttle valve closed position of the intake passage through a negative pressure passage, and the engine is connected to the negative pressure passage. A secondary air introduction device for an engine, characterized by intervening a valve that opens and closes depending on the operating state of the engine. 2. The secondary air introduction device for an engine according to claim 1, wherein the valve is of a type that opens when a low temperature of the engine is detected. 3. The secondary air introduction device for an engine according to claim 1, wherein the valve is of a type that opens when both a low temperature of the engine and a high vehicle speed are detected. 4. The secondary engine in the engine according to claim 1, wherein the negative pressure passage connected to the chamber on the other side is communicated with the negative pressure passage connected to the chamber on the one side via a side passage having a throttle. Air introduction device. 5. The secondary air introduction device for an engine according to claim 1, wherein a valve that is closed when the vehicle speed is low is interposed in the negative pressure passage connected to the chamber on one side.